Removing Alternator Tensioner on 300D - PeachParts Mercedes-Benz Forum

Chip · #1 11-16-2009, 09:53 AM

I'm removing the alternator on my 300DT and for the life of me I can't figure out how to loosen/remove the tensioner assembly to release the alternator. I have removed the bottom bolt, and the nut on the bolt that has the tensioner rod fixed to it. Is there one more bolt I must remove to get the tensioner free?

As it is, it seems a Catch-22 --- I can't get the top alternator bolt out with the tensioner rod in it, but I am unable to remove the tensioner rod. If I loosen it all the way, as if to remove the adjuster, the rod starts to bow and it becomes snug again.

Any help would be appreciated as I'm dead in the water till I get that out.

Graplr · #2 11-16-2009, 09:59 AM

You literally have to bend the bracket tab the holds the tensioner bolt in place. I use a pair of vice grips, attach it to the tab and bend it out just far enough to slip the bolt by. Then you can pull the bolt all the way out thus seperating the bracket from the alternator.

I know it is not to smart of a design but that is how it is done.

Chip · #3 11-16-2009, 10:09 AM

I can see how bending that tab would allow me to free the bolt, but I can't imagine that is the proscribed method for removing that bolt. I'd have to bend that tab nearly 90 degrees to allow the bolt to slip out. Plus, I'm not sure how I would get leverage on it to bend it that much. That's a pretty stout tab!

Graplr · #4 11-16-2009, 10:45 AM

Trust me. This is how it is done. I thought the same thing the first time I had to do it. But it can be confirmed by doing some searches here that this is the method.

Like I said, use vice grips and bend away. Then bend it back after you reinstall the bolt. It bends fairly easily.

tbomachines · #5 11-16-2009, 12:30 PM

Quote:

Originally Posted by Graplr

Trust me. This is how it is done. I thought the same thing the first time I had to do it. But it can be confirmed by doing some searches here that this is the method.

Like I said, use vice grips and bend away. Then bend it back after you reinstall the bolt. It bends fairly easily.

X2, only way I can think of too. Luckily the PO of my car pre-bent it

so its not too tough for me now. You might want to take the fan off to get more leverage, but look out for the radiator.

Graplr · #6 11-16-2009, 01:13 PM

Wait, I just reread the post. You don't need to take the tensioner bolt off to remove the alternator from the car. It is easier to just remove the enitre alternator bracket (tensioner bolt included). Then on the bench bend the tab to seperate the alternator from the bracket.

The alternator/bracket should be easily removed by taking 2 bolts out and possibly the nut on the back of the tensioner bracket main bolt.

Chip · #7 11-16-2009, 03:20 PM

Hey Grapir, thanks for your notes.

Indeed, newbie that I am, I didn't realize that the tensioner and the bracket came out with the alternator. I've seen on other boards I'm not the first newbie to be perplexed by that!

Once I realized that, and that the bolt onto which the tensioner is fixed was not the top bolt, I dug deeper, found the top bolt and off she came without a hitch. On the bench I did just as you said and was off and running.

In any case, I'm back up an running with a new (reman) Bosch and it's charging like a champ. I've had this car a week and am already madly in love with it. I love being able to fix my own business!

Wheeeee!

Graplr · #8 11-16-2009, 03:34 PM

Quote:

Originally Posted by Chip

Hey Grapir, thanks for your notes.

Indeed, newbie that I am, I didn't realize that the tensioner and the bracket came out with the alternator. I've seen on other boards I'm not the first newbie to be perplexed by that!

Once I realized that, and that the bolt onto which the tensioner is fixed was not the top bolt, I dug deeper, found the top bolt and off she came without a hitch. On the bench I did just as you said and was off and running.

In any case, I'm back up an running with a new (reman) Bosch and it's charging like a champ. I've had this car a week and am already madly in love with it. I love being able to fix my own business!

Wheeeee!

That is what this forum is for...help. We were all noobs once. Well, most of us anyways.

I definitely was not too long ago. In fact I still consider myself a noob compared to many on the forum. I just repeat a lot that I have learned from here.

Glad you got the new alternator on and all is working!

Be careful, these cars are addicting. Before you know it you may be obsessed like the rest of us.